I don't see any conspiracy to drive the price of Amarin down. Yesterdays action looked to me to be an institutional investor getting out of Amarin......something that was happening all over the market due to macro issues here and in China. The market news also coincides with the end of the 2nd qtr, so there is bound to be some rebalancing. AMRN at this point in time is event driven and the next probable event is the Aug CC.
The effects were exaggerated due to the fact that AMRN has been very thinly traded as of late. Lets not forget the big picture both for AMRN and the market in general. With a lack of price moving news for AMRN there is a tendency to try and read every price move and assign blame on sinister motives, dark forces and lurking evil. I don't see it. Some investors would still be burning witches at the stake if it were legal.